Electrical switch gear



July 21, 1936. 4 EHRENBE 2,048,496

ELECTRICAL SWITCHGEAR I Filed Jan. 10, 1954 2 Sheets-Sheet 2 a E 45 7 7 a Inventor:

Arthur c. Ehrenberg,

His Attorhey.

Patented July 2- 1, 1936 UNITED STATES PATENT OFFICE ELECTRICAL SWITCH GEAR Arthur Charles Ehrenberg, Tlmperley, England,

assignor to General Electric Company, a corporation of New York Application January 10, 1934, No. 706,142 In Great Britain January 20, 1933 6 Claims. (Cl. 200150) The invention relates to electrical switchgear and has for its object -the provision of an improved switch or circuit breaker of the double break type suitable for use in connection with currents of high voltage.

According to the invention the fixed contact and terminal structures of the'switch are housed in separate oil filled chambers or casings eachinsulated with respect to line potential and ground. The moving contacts with their supports and associated operating devices or rods are located within the bushings and their operation is controliedorefi'ected from the intermedirte casing which joins the ends of the bush- In carryingout the invention the intermediate and jterminal casings may be supported on hollow insulating columns or pillars of which at least those for the terminal casings are filled with oil or other insulating fluid. In some cases able contactsmay-beactuated' by pneumatic,-

the instrument or relay transformers or other apparatus associated with r the switches may be accommodated within'saidcolumns. v The movhydraulic,'mechanical or other means, these devices being operated or'controlledthrough the intermediate casing so that the twocontacts will be actuated substantially simultaneous y o erfeet a double break in the circuit. Where compressed air is employed as the} actuating means the conduits for the same may be carried within or by thejlnsulating column of the intermediate casing and thedistributingand exhaust valves controlling the operation may be located within the said casing and operated from'thel ground level by insulating mechanical connections.-

My invention will be more fully set forth in the following description referring to the ac con'lpanying drawings, and the featuresof nov-. elty which-characterize my invention pointed nout with particularity in; the claims annexedto and forminga part of -this'specifica--- A pneumatically operated double break switch circuit breaker suitable for voltages over 100,000

volts, and constructed-accordingt'o the invention will 'now'be described in. example, with and terminal struc tailed j description of reference to the accompanying drawings, in which, V

Fig. 1 is an elevational view of the switch. Fig. 1A is an enlarged view; partly in section, of a portion of the switch shown by Fig. 1.

Fig. 2 is a front view of a switch tank. detail drawn to an enlarged scale;

Fig. 3 is a section on the line A-A of Fig. 2. Fig. 4 is a section on the line 13-13 of Fig. 2. Fig. 5 is an elevation partly sectional of the compressed air valve operating mechanism, drawn to an enlarged scale and I Fig. 6 is a small scale plan view of the arrangement of'swltch or circuit breakers constructed according to the invention for a three-phase sys- Referring more particularly to Figs. 1 and 1A, the double-break switch or circuit breaker comprises relatively movable contacting members I, I, for interrupting the circuit, the contact and terminal member I being fixed and the member 2 movable. The member 2 is contained in ahorizontal bushing comprising a hollow insulating shell I mounted at one end in one sideof acasn: l- The casing 4 contains the fixed contacting member I and is carried on columns or pillars 5, 6 built of porcelainsections. The columns 5, 6 are oil-filled and may accommodate within them instrument or relay transformers or other apparatus associated with the switches as required. Further, the columns I, .6 may be utilized as conduits for renewing, circulating and/or filtermg the casing oil, in any well known manner. The otherend of thc'bushing 3 is mounted in one sided an intermediate casing or junction box "I which is carried-also on columns 8 built of porcelain sections. The junction-box I may conveniently be of aim and wallthickness which, by slight. deformation allows for thermal changes of dimeusi'onsin other related 'parts'oi' theapparatus.

The other pair of; contacts forming the double break switch is mounted'in'a similar on the other side of the iunctionbomjand only' one 6 side of the switch need therefore be describedin' detail.

The casing l an explosion pot or oil blast arc interrupting device 9 of'the." known type associated with theffixed, contact -l, whichis' suitably con-1 nected in'the circui ito befinterrupted: Adearc intemipting device 7 I isnotnecessary for a" generally indicated By way of example, an oil blast device having spaced insulating plates forming pressure exhaust passages of the type disclosed by Juhlin Patent 1,902,507 granted March 21, 1933 for Electrio circuit interrupters may be used. The casing 4 is further provided with a trapped air chamber III to absorb the pressure pulsations set up in the oil upon interruption of the circuit.

The horizontal bushing 3 comprises two sections ii, i 2, the section ii being mounted within the casing 4 and the section i2 lying outside the casing l, and this latter section is mounted at its other end in the junction box 1.

Running throughout the length of the bushing 3, and coaxial therewith is the insulating cylinder i3 which is closed at the casing end by means -of the bailie plate ll. The bafile H has a central orifice I5, so that the interior of the cylinder [3 is in communication with the interior of the tank 4. Between the bushing 3 and the cylinder iii any suitable arrangement of battles and/or condenser type conducting cylinders may be used according to known practice. 1

In the interior of the cylinder I3 is mounted a bearing member l8 wihch forms a'fixed terminal and also serves as a stufling box for a purpose to be hereinafter described. Electrical connection is made between the member l6 and the corresponding member in the bushing on the opposite side of the junction box by means of the cylinder 2i coaxial with the cylinder i3 and the junction member 36.

Electrical connection between the member I and the stationary contact i is made by means of the movable rod contact 2 which slides,

through the member IS in contact therewith, and is provided at-one end with a piston head IT. The piston l1 slides in a cylinder I8 coaxial with the insulating cylinder [3 and the cylinder i3 at one end is in communication with a supply of compressed air controlled by the valve mechanism l9 situated in the junction box 1, and which will be referred to hereinafter. The cylinder 13 is closed at the other end by the contact bearing member 15 which also serves as a stufllng box, the cylinder It being provided with apertures .23 near this end so that communication is established between the back face of the piston head i! and the space between the coaxial cylinders l8 and 2 I, which space is in communication with the compressed air supply through the valve mechanism. A metallic potential distributor 43 is provided as shown at theend of the cylinder II.

The casing I, the bushing 3, and the insulating cylinder l3 are filled with a suitable insulating liquid as oil, communication between the tank.

and the cylinder being made through the aper-. ture IE, but there is no communication between the oil in the bushing and the oil in the tank.

When an explosion occurs on the opening of the switch in the device 8 the pressure pulsations caused thereby 'are absorbed by the air trapped in the chamber II which communicates with the tank by the aperture 22. In order that the explosion pulsations originating in the oil in the tank 4 may be further cushioned by their effect upon the oil in the bushing 3 the device shown at 23 is provided. This device 23 comprises an annular chamber, the outer and inner cylindrical walls of which are perforated at the top, and the inner wall is provided'at the bottom with a series of apertures 25 over an arc, the length of which is indicated by the arrow 23 as shown in Fig. 2. A pipe 21, provided with a closing cap 23 passes through the apertures in the top of the inner and outer cylindrical walls in a fluid-tight manner, and through this pipe oil may be introduced into the bushingand into the annular chamber 23 through the apertures 23. The upper portion of the annular chamber will trap air to constitute an air cushion.

The compressed air valve mechanism situated in the junction box I is shown in detail in Fig. 5. The valve mechanism is contained within a casing I 9 situated on the bottom of the junction box I, and comprises an admission chamber 33 which communicates through the apertures 41 with the interior of the supporting column 3, and a discharge chamber 33 which communicates with the atmosphere through the pipe 39. The interior of the column 3 is supplied with compressed air in any known manner and two admission valves 23, 33 admit compressed air to one or the other side of the piston, in the one case through the pipe 3|, junction pipe 33 which connects the cylinders ll of each side of the switch in communication with each other, to the front face of the piston l1, and in the other case through the pipe 31, junction pipe 33 which connects the annular space between cylinders I3 and 2| of both sides of the switch together, through this said space, apertures 23 and interior of cylinder II to the back face of piston II.

The discharge valves 3| and 32 control the discharge of air from the piston cylinder 13. Thus, when the admission valve 33 is open to admit air to the front'ofthe piston the discharge valve 3| is open to allow the escape of air from the backface of the piston, the pistons 23 and 32 then remaining closed. In this case, the contacts I and 2 are closed. To separate these contacts, to open the circuit, the admission valve 23 and discharge valve 32 are opened, the valves 33 and 3| then remaining closed.

The valves are operated by means of the cams 40 and ll mounted on a central shaft 42 which is carried on the top of a central insulating col- ,umn 43, which is rotated in a well known manner by means of a push bar 43 situated at the base of the column 3.

Each valve is provided with the usual return spring and the admission valve stems are each provided at one end with a roller mounted on a spindle transverse to the stem, the rollers bearing on the internal surface of the hollow cam ll, whilst the stems of the discharge valves 3|, 32 bear on the cam surface of the disc 43.

Figure 6 shows a plan view of the arrangement of the double break switches as hereinbefore described, connected in each phase of a three-phase system. The central insulating columns 33 operating the cams l3 and ll and enclosed within each of the Jimction-box supporting columns 3, are simultaneously rotated by means of a push bar 3 connecting the insulating columns with 00 the operatingmechanism indicated at 44. The operation of the various switches may be controlled by individual controlling means if desired.

The connection between the push bar 43 and the central insulatingcolumn 33 is shown at the 66 foot of the central column in Figure l. and comprises a lug on the push bar which is pivotally connected to a forked lug on the base of the insulating column. -Any other convenient menu for rotating the central insulating column 70 through the angle required to operate the valves may be provided. 1 v

Although the bushings 3 have been hercinbe- 'fore described as situated horizontally, they may be inclined slightly upwards towards the junc- 76 tion box, so that air leaking out of the stumng box It need cause no trouble, as it will pass back along the space between the cylinders 2| and I l and be discharged at the junction box.

As hereinbei'ore mentioned it is necessary that the switch chambers and junction box shall be insulated from the ground so as to withstand continuously line to ground potential difl'erence. The insulation between the junction box and each of the switch casings or chambers need, however, only be such as to withstand continuously approximately one half the line to line potential diilference, but the insulation between the two switch chambers must be capable of withstanding the full potential difference between the lines.

It is to be understood that the various chambers hereinbefore described as being oil-filled gray be filled with any other suitable insulating uid.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

I claim:

1. A high voltage circuit breaker of the liquidbreak type comprising spaced stationary terminal structures, a casing positioned intermediate and spaced with respect to said terminal structures, a pair of insulating shells extending be-' tween and interconnecting said intermediate casing and said terminal structures, an insulating cylinder mounted within and extending longitudinally of each of said shells, an insulating liquid between. said each cylinder and shell, movable contact structure disposed in said cylinders for interrupting the circuit between said terminal structures, an insulating liquid in said cylinders sealed with respect to said first-named liquid, insulating pillars for supporting said terminal structures and said intermediate casing, said pillars insulating said terminal structures and easing with respect to line potential and ground, and operating means for said contact structure mounted within the intermediate casing and its supporting pillar.

g 2. A high voltage circuit breaker comprising a pair of oil-filled terminal casings, insulating supports for supporting and insulating said casings with respect to line potential and ground and a third casing positioned between and spaced with respect to said terminal casings, an insulating support for said third casing likewise insulating the same withrespect to line potential and ground, a pair of insulating shells interconnecting said third casing and said terminal casings, said shells containing oil sealed with respect to the oil in said casings, movable contact structure disposed in said insulating shells for interrupting the circuit, and operating mechanism for said contact structure extending into said third casing through its insulating support.

3. A high voltage circuit breaker oi the liquidbreak type comprising a pair of spaced terminal structures, an insulating supporting pillar for each of said terminal structures, an insulating cylinder containing an arc extinguishing liquid extending between said terminal structures, movable contact structure disposed within said insulating cylinder, a ceramic insulating shell sur- 4. A high voltage circuit breaker of the liquidbreak type comprising a pair of oil-filled casings, stationary contact and terminal structure disposed in said casings, a casing disposed intermediate'and spaced with respect to said terminal casings, a pair of insulating shells extending between and interconnecting said intermediate and terminal casings, an insulating cylinder disposed in each of said shells and extending within said terminal casings, a movable rod contact mounted within each of said cylinders for coacting with said stationary terminal structure, the

space between said cylinders and said shells being filled with insulating liquid sealed with respect to said terminal casings, insulating pillars for supporting said intermediate and terminal casings at substantially the same level and insulating said casings with respect to line potential and ground, and operating means disposed within the intermediate supporting pillar.

5. A high voltage circuit breaker of the liquidbreak type comprising an oil-filled casing, stationary contact and terminal structure mounted in said casing, a movable contact adapted to extend within said casing to coact with'the stationary contact, a hollow insulating shell within which said movable contact is operably mounted in said casing, saidmovable contact being enclosed and sealed with respect to the interior of said insulating shell, an insulating liquid in said shell sealed with respect to said casing, and an annular expansion chamber surrounding and in communication with said shell for relieving stress upon interruption oLthe circuit.

6. A high voltage circuit breaker oi the liquidbreak type comprising an insulating cylinder, movable contact structure disposed in said cylinder and immersed in an arc-extinguishing liquid, an insulating shell spaced from and enclosing said insulating cylinder, an insulating liquid in the space between said cylinder and shell, said liquid sealed with respect to saidarc-extingulshing liquid, and means forming an expansion chamber for the liquid in said shell'.

ARTHUR CHARLES EHRENBERG. 

